Method of making detonators



Nov.. 2 1926. i l,605,688

J. M. oLlN y|:1- AL METHOD OF MAKING DETONATORS Filed June 20, 1924 fig-5- Patented Nov. .2, 1926.

UNITED STATES PATENT OFFICE. i

JOHN M. OLIN AND JOHN B. SMITH, 0F ALTON, ILLINOIS, ASSIGNORS TO WESTERNCARTRIDGE COMPANY, OF EAST ALTON, ILLINOIS, A CORPORATION OF DELAWARE.

METHOD OF MAKING- DETONATORS.

Application tiled .Tune 20,

'lhis invention pertains lo detonators and more particularly to theigniters used in the same and lo a method for making the same.

One ol the objects of this invention is to provide an improved lnethodfor making ignilers for detonators and particularly for at. taching thefuse or filament to the igniter connections.

Another objectis to provide a method of making such connection withoutaltering the operating characteristics ot' the igniter.

Further objects will appeal' from the following description taken inconnection wit-h the accompanying drawing,-in Which,

Figure 1 is a cross sectional view somewhat enlarged of' a detonatorembodying this invention.

Figure 2 is a View illustrating the opera tion of notching theconnections.

.Figure 3 is a perspective View of the igniter plug with the connectionsnotched preparatoryto assemblingthe filament.

l `igure 4 is an enlarged diagrammatic view illustrating the operationot' swaging the connections to secure the filament; and

Figure 5 is a perspective view of the completed igniter with thefilament in place.

Referring to the accompanying drawing and morel particularly toFigure 1. the detonator shown comprises a shell 1. which may be ol drawnmetal, and has charge components 2 and 3 of any approved composition orarrangement, such as a mixture of picric acid and trinitro-toluenecapped by fulminate of mercury. The upper end of the shell is beaded asshown at 4. In this shell are arranged terminals 5 of the connectionswhich pass through a plug 7 formed on the connections and of a suitablecomposition, a satisfactory one being a mixture of sulphur and graphite.The connections are insulated Wires which are stripped from where theyproject through the plug and these connections are formed, ashereinafter described, to receive the filament 8. This filament may beof any suitable resistance wire, a satisfactory one being thecomposition of nickel, iron and copper. The plug with its terminals issecured Within the shell by additional plugs 9 and 10 of sulphur andpitch Which serve to seal andcap the shell and the terminals therein.-These plug components are poured into the shell so as to flow around theconnections and it will be noted that the 1924. Srial N0. 721,173.

composition flows into the bead l, so as to firmly secure and lock theparts together.

The plug 7 may be formed on the connection 6 and the ends of theconnections stripped of their insulation so as to provide the terminals5 in any suitable manner. A method for carrying out these operations isdescribed in co-pending application Serial No. 609,954, filed December30, 1922. After the plug 7 has been formed and the terminals strippedthe same may be mounted in 'a suitable die 11 cooperating with aV-shaped notching cutter 12, as illustrated in Figure 2. The cutter 12moves endwisein a groove 13 in the die 1-1. The terminals 5 project intothe groove 13 and as Vthe cutter 12 moves along the groove notches 14are cut in the ends of the terminals 5.

Upon the completion of the notching operation, the terminals have theform illustrated in Figure 3. Each terminal is notched at its end andthe notches lie in the same direction so that the filament may be laidin said notches so vas to bridge the gap between the terminals. Theigniter may then be mounted in any suitable support in cooperativerelation with a pair of swaging members 15. The members 15 are arrangedto be brought forcibly together upon the notched ends of the terminals 5so as to force the prongs thereof together upon the filament 8 whichnotches 14. This operation is illustrated in Figure 4. The tips of theterminals are thus reformed so as to be clamped upon the filament. Thefilament is thus securely held Without the use of solder' or othersecuring means Which is objectionable for the reason that it is liableto form a heavy coating on the filament and thus materially change theresistance thereof. A change of resistance of the filament alters itsoperating characteristics and affects reliability of ignition.

After the filament has been so secured, the filament and the terminalsof the igniter connections to Which it is attached are immersed in aprotective coating. This coating is preferably of non-conductive ma'ferial so as to leave the resistance of the filament unimpaired; it is,however, preferably also infiammable. A suitable Coating material .is asolution of nitro-cellulose in a suitable solvent such as ethyl-acetate;

has been laid in theimmersion of the filament and terminals in such asolution leaves a thin non-conducting but infiammable coating thereon.

When the swaging and coating operations have' been completed, theigniter is in the form illustrated in Figure 5 in which the filament 8is securely clamped in the ends of the terminals 5 and is bothelectrically and mechanically connected thereto without the use ofsolder or similar connecting means. The igniter is then ready l' orinsertion in the shell 1- of the detonator, as already described. Thecoating protccts the filament and terminals against corrosion, eitherfrom the sulphur of the plug or from the materials of the charge;accordingly it is not necessary to use expensive filament material likeplatinum, but base metal can be used as heretofore described. It will beclear, therefore, that this invention provides an improved igniter inwhich the Iilament is securely connected to the terminals, and a methodfor making `the same which is simple and which does not aiect theoperating characteristics of the igniter.

It is obvious that various changes may be made in the details ofconstruction Without departing from the spirit of this invention; it istherefore to be understood that the invention is not to be limited tothe specific details shown and described.

Having thus described the invention, what is claimed is:

l. In the art of making detonators, the method comprising, assembling a,air of igniter terminals in a plug, cutting V- notches in saidterminals, assembling a -filament in said notches, and crimping saidterminals on said filament.

2. In the art of making detonators, the method comprising, assembling apair of igniter terminals in a plug, cutting V- notches simultaneouslyin both of said terminals, assembling a filament in said notches, andcrimping said terminals on said filament.

3. In the art of making detonators, the method comprising, assembling apair of igniter terminals in a plug, cutting V- notches in saidterminals, assembling a filament in said notches, crimping saidterminals on said filament, and coating said filament.

4. In the art of making detonators, the method comprising, assembling' apair of igniter terminals in a plug, mounting said terminals in asupport, cutting V-notches in said supported terminals, assembling afilament in said notches, and crimping said terminals on said filament.

5. In the' art of making detonators, the method comprising, assembling apair of igniter terminals in aV plug, mounting said terminals in a die,passing a V-shaped cutter through said die to cut V-notches in saidterminals, assembling a filament in said notches, and crimping saidterminals on said filament.

In testimony whereof We aiiix our signatures this 6th day of June, 1924.

JOHN M. OLIN.

JOHN B. SMITH.

